88 FC electrical issue

What’s up guys, seeking some wisdom as I’ve finally decided to get this thing running again. Long story short, I got off work, warmed the car up, drove somewhere, parked for 2 hours, came back on and car wouldn’t click or crank. A buddy who also has an fc tried taking a look at it on the spot and nothing so we towed it. I took it to a respected rotary shop around here and he said it was the engine harness and that my terminals were too small and at any moment it could’ve caught on fire so he didn’t touch it further. So far I’ve changed

Fuel pump Bypassed clutch switch Battery Terminals Spark plugs Fuses are all good

After buying a red top battery and hoping that was the issue, still stayed the same. All lights will come on but won’t click or crank, I’ve never encountered this issue before and it’s been sitting in my garage for far too long. Thanks in advance guys.

P.S: The cracked bumper and dented hood is from an old lady backing her truck into me at work ha. I’ll be swapping those in the spring